Takahashi Rie, Okamura Kanno, Tsukahara-Kawamura Tomoko, Harada Kazuhiro, Saeki Yusuke, Ozaki Hiroaki, Uchio Eiichi
Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan.
Clin Ophthalmol. 2020 May 26;14:1445-1450. doi: 10.2147/OPTH.S249483. eCollection 2020.
We have carried out three-dimensional finite element analysis (FEA) to determine the physical and mechanical response in several ocular injuries. We applied this FEA model to evaluate an airsoft gun impact on an eye and the deformation rate of eyes of various axial lengths at various velocities.
This study was carried out on a human eye model using an FEA program created by Nihon, ESI Group. The airsoft gun pellet was set to impact the eye at initial velocities of 45, 60 and 75 m/s with the addition of variation in axial length of 20 mm (hyperopia), 22 mm (emmetropia), 24 mm (myopia) and 26 mm (high myopia). Deformation of the eye was calculated as the decrease rate of the volume of the eyeball and the decrease rate of the axial length.
In all emmetropic cases, the cornea reached its strain threshold during the impact, and scleral strain showed a patchy strength distribution in the simulation. The deformation was most evident in the anterior segment, while deformation of the posterior segment was less. The decrease rate of the volume of the eyeball and decrease rate of the axial length were highest in the hyperopic eye, followed by the emmetropic eye and myopic eye, and the high myopic eye showed the lowest decrease rates among the four axial lengths in all impact velocity simulations.
These results suggest that hyperopic eyes are most susceptible to deformation by an airsoft gun impact compared with other axial length eye models in this simulation. The considerable deformation by an airsoft gun impact shown in this study might indicate the necessity of ocular protection to avoid permanent eye injury. FEA using a human eyeball model might be a useful method to analyze and predict the mechanical features of ocular injury by an airsoft gun.
我们进行了三维有限元分析（FEA），以确定几种眼部损伤中的物理和力学响应。我们应用此有限元分析模型来评估气枪对眼睛的冲击以及不同轴向长度的眼睛在不同速度下的变形率。
本研究使用由日本电研ESI集团创建的有限元分析程序，在人眼模型上进行。气枪子弹以45、60和75米/秒的初始速度冲击眼睛，并增加了轴向长度的变化，分别为20毫米（远视）、22毫米（正视）、24毫米（近视）和26毫米（高度近视）。眼睛的变形通过眼球体积的减少率和轴向长度的减少率来计算。
在所有正视情况下，角膜在冲击过程中达到其应变阈值，并且在模拟中巩膜应变显示出斑块状强度分布。变形在前部最为明显，而后部的变形较小。眼球体积的减少率和轴向长度的减少率在远视眼中最高，其次是正视眼和近视眼，在所有冲击速度模拟中，高度近视眼在四个轴向长度中显示出最低的减少率。
这些结果表明，在该模拟中，与其他轴向长度的眼睛模型相比，远视眼最容易受到气枪冲击的变形影响。本研究中显示的气枪冲击造成的相当大的变形可能表明有必要进行眼部保护以避免永久性眼损伤。使用人眼球模型的有限元分析可能是一种分析和预测气枪造成眼部损伤的力学特征的有用方法。
